The present invention relates to brush holder assemblies for electrical motors. More specifically, it relates to brush holder assemblies for use with electrical motors commonly employed in small electric appliances and hand tools, the latter category including, for example, drills, sanders, and saws. In the usual case, such brush assemblies are spring biased to maintain good electrical contact between the carbon brush and the motor commutator. As the carbon brushes wear down, there is a danger of damaging the motor by scoring the commutator if the brush is cast out of the housing and the spring, the terminal connector or the conductor contacts the commutator.
To prevent this kind of damage restraining elements have been developed to prevent movement of the brush assembly after the brush wears down to a predetermined size. Those constructions, however, have not been entirely satisfactory both as to cost and function and, accordingly, there is a need for an improved brush holder construction which achieves the desired objective.
It is accordingly an object of the present invention to provide improved brush holder assemblies which prevent discharge of the spring, terminal connector and conductor from the brush housing to a position where it can damage the motor commutator.
A further object of the invention is to provide improved brush holder assemblies of the type referred to in the preceding paragraph which are low in cost and simple in construction permitting rapid assembly into completed devices.
A further object of the invention is to provide a brush holder terminal connector having an integral mechanism for preventing movement of the terminal connector beyond the brush housing.
A further object of the invention is to provide an improved terminal connector having means for engaging the walls of the brush housing, when the brush has worn down to a predetermined size, to prevent further movement of the brush assembly.
Other objects and advantages of the invention will be apparent from the remaining portion of the specification.